[Crowbar] [SPAM] RE: Size of your OpenStack Deployment?

Gregory_Althaus at Dell.com Gregory_Althaus at Dell.com
Tue Jan 24 08:51:46 CST 2012

Thanks Kevin.

For crowbar, the flat mode uses the network controller as a gateway.  I got tired of not having a routed/outbound path.  It also makes the code more concise because all modes use the network controller as the router (even HA modes though there are many).  I think (okay, I got more sure over time); I haven't used it in a while either.  It is a little different than Vish's document.  It is a way to implement it.


-----Original Message-----
From: crowbar-bounces On Behalf Of Kevin Bringard
Sent: Tuesday, January 24, 2012 8:43 AM
To: crowbar
Subject: Re: [Crowbar] Size of your OpenStack Deployment?

This is only partially correct; you are correct that in Flat mode nova doesn't do anything with networking... it'll just spin up a VM and assume that you have everything setup to properly assign an IP, route to the meta-data API, etc. I believe floating IPs are still handled by the network-controller, though, but I'm not 100% sure (I've never used Flat mode).

In FlatDHCP mode the network controller is the default gateway for VMs by default (unless you pass them a different gateway via the dhcpoption=3,<gateway IP> in the dnsmasq.conf). Vms will also not get an external address automatically unless you specify --auto_assign_floating_ip=true in your nova.conf. By default it will NAT out through the network controller (and all Vms will source from the same external IP until they are assigned a floating ip).

If you're interested in a good quick overview of networking in nova, this is a great blog (written by Vishy):

-- Kevin

From:  Neil Jubinville <neil at orbitalsoftware.ca>
Reply-To:  "neil at orbitalsoftware.ca" <neil at orbitalsoftware.ca>
Date:  Mon, 23 Jan 2012 22:08:32 -0800
To:  "crowbar at dell.com" <crowbar at dell.com>
Subject:  Re: [Crowbar] Size of your OpenStack Deployment?

    FYI - In both flat modes, the network
      nodes do not act as a default gateway. Instances are given public
      IP addresses. Compute nodes have iptables/ebtables entries created
      per project and instance to protect against IP/MAC address
      spoofing and ARP poisoning.
    On 1/23/2012 10:55 PM, Shake Chen wrote:

      On Tue, Jan 24, 2012 at 12:19 AM, Gregor
        von Laszewski <laszewski at gmail.com>
                 I was wondering about the current size of your
          deployments and which versions you are running.  Can you let
          me know?
                 We are trying to put together a relatively large
          deployment across several clusters and before we co down the
          wrong path we like to get your feedback. We have more than
          4000 cores in our testbed.
          How many servers are dedicated to Openstack?

        about 100 server at the first step.
          Are you running multiple Zones?

          I think I need the feature, but not test.
          How many VMs are you managing with your OpenStack deployment?

        Abount 1000 VM
          Which version of OpenStack do you run?

        Essex in Ubuntu 12.04, I hope
          Have you encountered any difficulties that one should

          how the monitor the haddisk and raid?
          maybe also need to consider how to avoid ARP attack.
          Is there a contact person that I can talk to about your

          you can contact me .
          Shake Chen ( shake.chen at gmail.com)
            Gregor von Laszewski
            Crowbar mailing list
            Crowbar at dell.com
            For more information:

      msn:shake.chen at hotmail.com
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         Neil Jubinville
        Orbital Software Solutions Inc.
        neil at orbitalsoftware.ca

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